Tested x86_64-linux.
-- >8 --
PR 116529 shows that std::unique_ptr<X&, D> is currently unusable
because the constructor taking std::auto_ptr (which is a non-standard
extension since C++17) tries to form the invalid type X&* during
overload resolution. We can use the `pointer` type in the constructor
constraints, instead of trying to form an invalid type. The
std::auto_ptr constructor can never actually match for the case where
element_type is a reference, so we just need it to produce a
substitution failure instead of being ill-formed.
LWG 4144 might make std::unique_ptr<X&, D> ill-formed, which would
invalidate this new test. We would have to remove this test in that
case. Using `pointer` in the constructor from std::auto_ptr would not be
needed to support the std::unique_ptr<X&, D> case, but would not cause
any harm either.
libstdc++-v3/ChangeLog:
PR libstdc++/116529
* include/bits/unique_ptr.h (unique_ptr(auto_ptr<U>&&)):
Use pointer instead of T*.
* testsuite/20_util/unique_ptr/creation/116529.cc: New test.
---
libstdc++-v3/include/bits/unique_ptr.h | 5 +--
.../20_util/unique_ptr/creation/116529.cc | 35 +++++++++++++++++++
2 files changed, 38 insertions(+), 2 deletions(-)
create mode 100644 libstdc++-v3/testsuite/20_util/unique_ptr/creation/116529.cc
diff --git a/libstdc++-v3/include/bits/unique_ptr.h
b/libstdc++-v3/include/bits/unique_ptr.h
index 0f600db32f9..edcff78bff9 100644
--- a/libstdc++-v3/include/bits/unique_ptr.h
+++ b/libstdc++-v3/include/bits/unique_ptr.h
@@ -379,8 +379,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
/// Converting constructor from @c auto_ptr
- template<typename _Up, typename = _Require<
- is_convertible<_Up*, _Tp*>, is_same<_Dp, default_delete<_Tp>>>>
+ template<typename _Up,
+ typename = _Require<is_convertible<_Up*, pointer>,
+ is_same<_Dp, default_delete<_Tp>>>>
unique_ptr(auto_ptr<_Up>&& __u) noexcept;
#pragma GCC diagnostic pop
#endif
diff --git a/libstdc++-v3/testsuite/20_util/unique_ptr/creation/116529.cc
b/libstdc++-v3/testsuite/20_util/unique_ptr/creation/116529.cc
new file mode 100644
index 00000000000..323fc7cb27c
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/unique_ptr/creation/116529.cc
@@ -0,0 +1,35 @@
+// { dg-do run { target c++11 } }
+
+// Bug libstdc++/116529 - Construction of unique_ptr with reference type
+// is rejected because of auto_ptr constructor
+
+#include <memory>
+#include <testsuite_hooks.h>
+
+int count = 0;
+
+struct X
+{
+ ~X() { ++count; }
+};
+
+struct deleter : std::default_delete<X>
+{
+ using pointer = X*;
+};
+
+void
+test01()
+{
+ {
+ std::unique_ptr<X&, deleter> up(new X);
+ // { dg-bogus "forming pointer to reference" "" { target *-*-* } 0 }
+ VERIFY( count == 0 );
+ }
+ VERIFY( count == 1 );
+}
+
+int main()
+{
+ test01();
+}
--
2.46.0
